In response to the queries from your manager, the information that the SNMP agent retrieves is called a variable binding and is uniquely identified by an object identifier (OID). For instance, the OID 1.3.6.1.2.1.1.3 is defined for the 'up-time of agent' value.

All SNMP messages are sent as protocol data units (PDU). A PDU consists of a header and a variable binding. A PDU can be of the following types: GET, SET, BULKGET, GETNEXT, or NOTIFICATION. A PDU of the GET or NOTIFICATION type is an asynchronous notification and also called a trap. The manager can set alerts in OEM to receive traps when an alert is triggered. In response to receiving a trap, the manager performs a recording action, such as sending an e-mail or recording a statistic. Depending on your SNMP environment configuration, the trap is sent to a specific host or to a broadcast address. The description for all the traps for possible OEM alerts is stored in the OEM MIB file, PSC-FM-MIB.txt, available at the <OpenEdge-install-dir>/config location.

In SNMP version 2c, you can assign users to read and write access to the SNMP agent. SNMP version 3 adds security enhancements to the SNMP version 2c functionality. SNMP version 3 authenticates users to access the SNMP agent and relies on a User-based Security Model (USM) for providing 3 security levels:

Communication without authentication and privacy (NoAuthNoPriv)

Communication with authentication and without privacy (AuthNoPriv)

Communication with authentication and privacy (AuthPriv)

The minimum security level required is NoAuthNoPriv.

Note: The security configuration of the SNMP manager must match the OEM SNMP security configuration. For example, if you are using SNMP version 3 with AuthNoPriv in OEM, the SNMP manager must be configured to use SNMP version 3 with AuthNoPriv.

If you have installed the SNMP Adapter, you can change the current SNMP Adapter settings.

To change the SNMP Adapter settings:

1. From the management console menu bar, click Options.

The Options page appears.

2. Click SNMP Adapter.

The SNMP Adapter page appears and displays the SNMP agent status and information.

3. Click Edit. You can set the SNMP version and one or more of the following settings:

SNMP Version— The version of SNMP.

SNMP agent port— The port number of the host machine on which the SNMP management agent resides. The SNMP agent translates the requests from the SNMP management console and interprets MIB variables. The default port number is 8001.

Default SNMP trap port— The default port number to which traps are sent. The default port number is 8002.

If you set the SNMP version as Version 2c, set the following options:

Default SNMP read community — The community that specifies who has permissions to read which variables.

Default SNMP write community — The community that specifies who has permissions to write which variables (in the case of the OpenEdge Management MIB, the values are read-only.)

If you set the SNMP version as Version 3, set the following options:

Security Name — The SNMP security user name. This user name is required to access the SNMP agent.